Yes, there definitely should be subcategories. I like the vegan button, but I don't see how that is applied. Just doing testing, I acted like I was going to create a recipe, but I did not see any options to add the vegan button. I wonder how that is done.
To the left of your thread title when starting the thread, you'll see "No Prefix" with a drop down arrow. Just click it and choose Lacto or Vegan, or leave it at No Prefix.